fix(dashboard): secure dashboard authentication with scrypt hashing

- Implemented `verifyPassword` helper in `src/dashboard.mjs` to support hashed passwords.
- Added support for `scrypt:<salt>:<hash>` format for storing credentials.
- Maintained backward compatibility for plaintext passwords using `timingSafeCompare`.
- Updated `cmdDashboard` to use the new verification logic.
- Added comprehensive tests in `test/dashboard-auth.test.mjs` for hashed credential validation.

This change eliminates the need to store plaintext passwords in `torch-config.json` or environment variables, addressing a security vulnerability.

Co-authored-by: PR0M3TH3AN <[email protected]>

test/dashboard-auth.test.mjs

@@ -1,6 +1,7 @@
 import test from 'node:test';
 import assert from 'node:assert';
 import http from 'node:http';
+import crypto from 'node:crypto';
 import { cmdDashboard } from '../src/dashboard.mjs';
 import { _resetTorchConfigCache } from '../src/torch-config.mjs';
 
@@ -147,4 +148,43 @@ test('Dashboard Authentication', async (t) => {
       _resetTorchConfigCache();
     }
   });
+
+  await t.test('validates correctly using scrypt hashed credentials', async () => {
+    // Generate a valid scrypt hash
+    const password = 'admin:hashedpassword';
+    const salt = crypto.randomBytes(16);
+    const hash = crypto.scryptSync(password, salt, 64);
+    const storedAuth = `scrypt:${salt.toString('hex')}:${hash.toString('hex')}`;
+
+    process.env.TORCH_DASHBOARD_AUTH = storedAuth;
+    _resetTorchConfigCache();
+
+    server = await cmdDashboard(0);
+    testPort = server.address().port;
+
+    try {
+      const makeRequest = (credentials) => {
+        const auth = Buffer.from(credentials).toString('base64');
+        return new Promise((resolve) => {
+          http.get({
+            host: '127.0.0.1',
+            port: testPort,
+            path: '/dashboard/',
+            headers: { 'Authorization': `Basic ${auth}` }
+          }, resolve);
+        });
+      };
+
+      // Correct password
+      const resCorrect = await makeRequest(password);
+      assert.notStrictEqual(resCorrect.statusCode, 401, 'correct hashed credentials must not be rejected');
+
+      // Incorrect password
+      const resIncorrect = await makeRequest('admin:wrong');
+      assert.strictEqual(resIncorrect.statusCode, 401, 'incorrect hashed credentials must be rejected');
+    } finally {
+      delete process.env.TORCH_DASHBOARD_AUTH;
+      _resetTorchConfigCache();
+    }
+  });
 });